Possibly a bit boring, but practical:

Chicken + Rice
Spray chicken with 1kcal spray oil and then liberally coat with a seasoning mix of your choice (e.g. http://www.schwartz.co.uk/productdetail.cfm?id=5174)
Put on a tray and stick it in the oven (set to 225º)
Important part (which I tend to forget) - set a timer for 30mins minus however long your side dishes take to cook

I tend to go for microwave rice (2 mins nad tasty) with microwave steam veg (3 mins), so I'd set a timer for 25 mins and cook the veg and then the rice.

Prep time is short and it only takes a couple of mins (if that) to dish up.

I also like to cook up chocolate cake for special occasions, but that takes >40 mins and is fairly labour intensive at the start and end of the cooking process.